Herbicidal bis-urea and urea-carbamoyl sulfides

ABSTRACT

Herbicidal compounds of the formula   wherein R1 is hydrogen or alkyl; R2 is alkyl or monocyclic aryl; R3 and R4 individually are hydrogen, alkyl or aryl; and R5 is (a) -NR6R7 wherein R6 is hydrogen or alkyl and R7 is alkyl or monocyclic aryl; or (b) -OR8 wherein R8 is monocyclic aryl.

Brown, deceased et al. Dec. 9, 1975 [5 HERBICIDAL BIS-UREA AND 3,824,2817/l974 Brown ll/98 x uREAcmBAMoYL SULFIDES l FOREIGN PATENTS ORAPPLICATIONS [75] Inventors; Melancthon S. Brown, deceased, ate F ofBerkeley, Calif; by Gustave K. 1041440 German) Kohn. administrator.Berkeley, Calif Prlmary Exammer.lames 0. Thomas Jr, Attorney, Agent, orFirmJ. A. Buchanan Jr.; John [73] AssIgnee: Chevron Research Company,San Stoner 1 Raymond Francisco, Calif.

[22] Filed: Mar. 14, 1974 [57] ABSTRACT {2]} Appl 450965 Herbicidalcompounds of the formula Related US. Application Data [63]Continuation-impart of Ser. No. 189,732, Oct. l5,

l9? I, abandoned, which is a continuation-in-pafl of O 1 Ser. No 88,2l2,Nov. 9. I970. Pat. No. 3,755,437, H S which is a continuationin-part ofSer No 250907, IL L May 8 I972, said Ser. No 250907 is a continuation- 1in-partofSer. N0 189.732.0ct l5. I971,

2 Cl. 71 wherein is alkyl; R2 is alkyl or mono {g Cl 2 AOIN cyclic aryl;R and R IndIvidually are hydrogen, alkyl [58] Fie'ld 71/98 or aryl; andR is (a) NRR wherein R is hydrogen or alkyl and R is alkyl or monocyclicaryl; or (b) [56] References Cited OR wherein R is monocyclic aryl,

UNITED STATES PATENTS 14 Claims, N0 Drawings 3,770,826 [H1973 Schubartet al, 260/558 S HERBICIDAL BIS-UREA AND UREA-CARBAMOYL SULFIDESCROSS-REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of application Ser. No. 189,732, filed Oct. 15,1971, now abandoned, which in turn is a continuation-in-part ofapplication Ser. No. 88,212, filed Nov. 9, 1970, now US. Pat. No.3,755,437. This application is also a continuation-in-part ofapplication Ser. No. 250,907, filed May 8, 1972, which is, in turn, acontinuation-in-part of application Ser. No. 189,732, filed Oct. 15,1971 and of application Ser. No. 88,212, filed Nov. 9, 1970, now US.Pat. No. 3,755,437. The disclosures of US. Pat. No. 3,755,437, Ser. No.250,907 and Ser. No. 189,732 are incorporated herein by reference.

DESCRIPTION OF RELATED ART German application No. 2,131,399 of BadischeAnilin-and Soda-Fabrik, published Dec. 28, 1972, discloses thepreparation of N,'N'-disulfides of N-methylcarbamates by reacting anN-methylcarbamate with a disulfur dihalide.

DESCRIPTION OF THE INVENTION The compounds of the invention arerepresented by the formula gtt e t...

wherein R is hydrogen or alkyl of 1 to 6 carbon atoms; R is alkyl of 1to 6 carbon atoms or phenyl substituted with up to 4 (0 to 4),preferably up to 2 (0 to 2) fluorine, chlorine, bromine, nitro, alkyl of1 to carbon atoms, alkoxy of 1 to 4 carbon atoms, or up to 1 (0 to l)trifluoromethyl or trichloromethyl, R and R individually are hydrogen,alkyl of l to 6 carbon atoms or phenyl substituted with up to 4,preferably up to 2, fluorine, chlorine, bromine, nitro, alkyl of 1 to 5carbon atoms, alkoxy of 1 to 4 carbon atoms, or up to l trifluoromethylor trichloromethyl; and R is (a) NR R" wherein R is hydrogen or alkyl of1 to 6 carbon atoms and R is alkyl of l to 6 carbon atoms or phenylsubstituted with up to 4, preferably up to 2, fluorine, chlorine,bromine, nitro, alkyl of 1 to 5 carbon atoms, alkoxy of 1 to 4 carbonatoms, or up to 1 trifluoromethyl or trichloromethyl, or (b) OR whereinR is phenyl substituted with up to 4, preferably up to 2, fluorine,chlorine, bromine, nitro, alkyl of l to 5 carbon atoms, alkoxy of 1 to 4carbon atoms, or up to l trifluoromethyl or trichloromethyl.

Representative alkyl groups which R, R R R, R and R may representinclude methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl and hexyl.

Representative aryl groups which R R R, R and R may represent includephenyl, o-fluorophenyl, pfluorophenyl, o-chlorophenyl, m-chlorophenyl,2,4- dichlorophenyl, 3,5-dichlorophenyl, 3,4-dichlorophenyl,m-bromophenyl, o-trifluoromethylphenyl, p-trichloromethylphenyl,p-tolyl, p-ethylphenyl, 3,5- methylphenyl, p-nitrophenyl,p-methoxyphenyl, m-

2 butoxyphenyl, 2-fluoro-4-methylphenyl and 2-nitro-4- chlorophenyl.Preferred aryl groups are phenyl substituted with up to 2 fluorine,chlorine, bromine or alkyl of 1 to 5 carbon atoms. The most preferredaryl groups 5 are phenyl substituted with up to 2 fluorine, chlorine orbromine.

One class of preferred bis-urea sulfides of Formula I (R equal to NR Ris that wherein R and R are hydrogen; R and R are the same and arephenyl substituted with up to 2 fluorine, chlorine, bromine, nitro,alkyl, alkoxy or up to 1 trifluoromethyl or trichloromethyl, morepreferably phenyl substituted with up to 2 fluorine, chlorine orbromine; and R and R are the same and are alkyl.

Another class of preferred bis-urea sulfides are those wherein R ishydrogen or alkyl, more preferably hydrogen; R and R individually arealkyl or phenyl substituted with up to 2 fluorine, chlorine, bromine,nitro, alkyl, alkoxy or up to l trifluoromethyl or trichloromethyl, morepreferably phenyl substituted with up to 2 fluorine, chlorine, bromineor alkyl; R is phenyl substituted with up to 2 fluorine, chlorine,bromine, nitro, alkyl, alkoxy, or up to l trifluoromethyl ortrichloromethyl; R and R individually are alkyl.

The most preferred class of bis-urea sulfides are those wherein R and Rare the same and are hydrogen or alkyl, most preferably hydrogen; R andR are the same and are phenyl substituted with up to 2 fluorine,chlorine, bromine, nitro, alkyl, alkoxy, or up to 1 trifluoromethyl ortrichloromethyl, most preferably phenyl substituted with up to 2fluorine, chlorine or bromine.

A preferred class of urea-carbamoyl sulfides of Formula I (R equal toOR) is that wherein R is hydrogen, R is alkyl or phenyl substituted withup to 2 fluorine, chlorine, bromine, nitro, alkyl, alkoxy, or up to 1trifluoromethyl or trichloromethyl, more preferably up to 2 fluorine,chlorine, bromine or alkyl; R is alkyl; R is alkyl; and R is phenylsubstituted with up to 2 fluorine, chlorine, bromine or alkyl, morepreferably phenyl substituted with up to 2 alkyl.

Representative bis-urea sulfides of Formula I include:

bis-( 3-phenyll -ureido) sulfide,

bis-( 1-methyl-3-phenyll-ureido) sulfide,

bis-( 1-methyl-3-o-fluorophenyl- 1 -ureido) sulfide,

bis-( 1-methyl-3-p-fluorophenyll-ureido) sulfide,

bis-( 1-methyl-3-m-chlorophenyl-1 -ureido) sulfide bis-( 1-methyl-3-[ 3,4-dichlorophenyl 1 -ureido) sulbis-( 1-methyl-3- 2,4-dibromophenyl 1-ureido bis-( l-methyl-3-o-nitrophenyll-ureido) sulfide,

bis-( l-methyl-3-p-methoxyphenyl-l -ureido) sulfide,

bis-(1-methyl-3-m-methylphenyl-l-ureido sulfide, bis-t 1-methyl-3-[2-nitro-4-methoxyphenyl]- l ureido) sulfide,

bis-( 1-ethyl-3-[ 2,3,4,5-tetrachlorophenyl]- 1 -ureido) bis-(1-pr0pyl-3-[3,5-diethoxyphenyl1-l-ureido) sulbis-(1-methyl-3-methyl-3-o-chlorophenyll -ureido) 1-methyl-3-p-chlorophenyl-1 -ureido-1 '-p-ch1orop heny1-3 '-methyl-1-ureido sulfide,

nitro-4-methoxyphenyl )-3 -methyl-1 -ureido fide, and

l-methyl-3-o-chlorophenyll ureido-l '-chloromethyl-3'-ethyl-1-ureidosulfide.

sul-

sul-

3 4 Representative urea-carbamoyl sulfides of Formula ether; andcycloalkyl ethers, e.g., dioxane, tetrahydro- Include; furan andtetrahydropyran. Other suitable diluents in-(l-methyl-3-p-chlorophenyl-l-ureido)-(phenylcarclude nitriles such asacetonitrile and propionitrile; amoyll sulfide, dialkylamides such asdimethylformamide and dialkyll-methyl-3-ofluorophenyll-ureido)-(o-fluorophesulfoxides such as dimethylsulfoxide. Preferreddilue nts nyl-N-methylcarbamoyl sulfide, are chlorinated hydrocarbons of1 to 2 carbon atoms, 11-methyl-3-o-nitrophenyl-l-ureido)-(3-bromophesuchas methylene dichloride, chloroform, carbon tetnyl-N-methylcarbamoyl)sulfide, rachloride and ethylene dichloride. Generally, the(3-methyl-l-o-tolyl-l-ureido)-(2,3,4,5 tetraamount of diluent employedranges from 1 to 50 mols chlorophenyl-N-methylcarbamoyl) sulfide, andper mol of N-chlorothio urea reactant.(l-methyl-3-o-trifluorophenyl-l-ureido)-(3-sec- The reaction is suitablyconducted at a temperature butylphenyl-N-methylcarbamoyl) sulfide.between C. and the boiling point of the diluent, al- The compounds ofthe invention are prepared by rethough temperatures between 0 and 50C.are preacting an N-chlorothiourea and a urea (lll, R ferred. Thereaction is conducted at or above atmo- NR R or a carbamate (III, R ORas de- 15 spheric pressure. picted in equation l The bis-urea sulfide orurea-carbamoyl sulfide prod- R 0 so 0 R o o l ll l /NCN\ HNCR5 B /NC-N-s ri-i c R- B-HCl R2 R3 -l R? R3 R4 1") (ill) (1V) (I) wherein R, RR, R and R have the same signifiuct is recovered and purified byconventional procecance as previously defined, and B is an acidacceptor. dures such as extraction, crystallization, chromatogra- Theacid acceptor is an inorganic base, e.g., alkali phy, etc. metalhydroxide, bicarbonate or carbonate, or an or The N-chlorothio ureareactant (II) is prepared in acganic nitrogen base such as a pyridinecompound or a cordance with the following reaction (2):

R 0 H R o SCI m-fl-N $0 B' Nl N B'-HCI R R R R 2 trialkylamine. Suitablepyridine compounds are pyriwherein R, R and R have the same significanceas dine and pyridine compounds of 6 to 10 carbon atoms previouslydefined and B is an acid acceptor.

and of l to 2 alkyl groups such as 2-methylpyridine, 2- 40 The acidacceptor is an organic base such as a pyriethylpyridine,3-methylpyridine, 3,5-dimethylpyridine, dine compound or a trialkylaminecompound. The preand 2-butylpyridine. Suitable tralkylamines are thoseferred acid acceptor is a pyridine compound, especially wherein thealkyl group contains individually l to 4 pyridine.

carbon atoms, such as trimethylarnine, triethylarnine, Generally,commercially available sulfur dichloride tripropylamine andtributylamine. The preferred acid of reasonable purity, e.g., greaterthan 90-98% purity,

acceptors are pyridine compounds, especially pyridine. is suitablyemployed. The sulfur dichloride may contain The N-chlorothio ureareactant (II) and the urea or small amounts of an inhibitor such astributylphosphate carbamate (III) are employed in substantially equimoortriethylphosphate.

lar amounts, e.g., the molar ratio of the N-chlorothio The sulfurdichloride and the urea (V) are employed urea reactant (11) to the ureaor carbamate (1") generin substantially equimolar amounts, e.g., themolar ally varies from about 1.521 to 1:15, although molar ratio ofsulfur dichloride to the urea compound generratios of (II) to (III) ofabout 1.211 to 111.2 are preally varies from about 1.521 to 111.5,although molar ferred. The molar ratios of acid acceptor to the N-ratios of sulfur dichloride to the urea compound of chlorothio ureareactant are also substantially equimo- 1.4:1 to 1.111 are preferred.The molar ratios of acid lar, e.g., the molar ratio of acid acceptor toN- acceptor to sulfur dichloride are also substantially equichlorothiourea reactant varies from about 1.511 to molar, e.g., the molar ratio ofacid acceptor to sulfur 121.5, although molar ratios of acid acceptor toN- dichloride varies from about 15.1 to 1:1.5, although chlorothio ureareactant of about 1.2:1 to 121.2 are premolar ratios of acid acceptor tosulfur dichloride of 1:1 ferred. to 111.2 are preferred.

The reaction depicted in equation 1 is generally ac- In general, thereaction depicted in equation (2) is complished by reacting theN-chlorothio urea reactant accomplished by reacting the urea and thesulfur di- (I1) and the urea or carbamate (III) in the presence ofchloride in the presence of the acid acceptor comthe acid acceptor inthe liquid phase in an inert diluent. pound in the liquid phase in aninert diluent, e.g., dilu- Suitablc inert diluents for the reactioninclude alkanes ents employed for the reaction of the N-chlorothio ureaof 5 to 10 carbon atoms. such as hexane, isooctane and reactant and theurea or carbamate. The reaction is decane', aromatic compounds such asbenzene and suitably conducted by adding the sulfur dichloride to achlorobenzene; oxygenated hydrocarbons such as acymixture of the ureaand the acid acceptor in an inert clic alkyl ethers, e.g.,dimethoxyethane and dibutyl diluent. Alternatively, the reaction isconducted by adding a mixture of the urea and acid acceptor to asolution of the sulfur dichloride in an inert diluent. However, thepreferred method for conducting the reaction comprises reacting the ureaand sulfur dichloride in the presence of a limited amount of free,uncomplexed acid acceptor. This is suitably accomplished by the additionof the acid acceptor to a substantially equimolar mixture of the ureaand the sulfur dichloride, so that the mols of free acid acceptor to thetotal mols of urea reactant and N-chlorothio urea product is less than0.2:1, preferably less than 0.1:1, and more preferably less than 0.05:].In other words, during the course of the reaction between the sulfurdichloride and the urea reactant, there should be at least 5 mols of theurea reactant and the N-chlorothio urea product per mol of acid acceptorwhich is not complexed with hydrochlorid acid. Provided that thereaction is conducted with the restricted amount of acid acceptorindicated above, the contacting of the acid acceptor with the mixture ofthe urea and the sulfur dichloride can be conducted by a variety ofprocedures. In one modification, the acid acceptor is added inincrements, e.g., dropwise, in an inert diluent, if desired, to amixture of the urea and sulfur dichloride in an inert diluent. Inanother modification, the acid acceptor is added continuously to amixture of the urea and sulfur dichloride in an inert diluent.

The N-chlorothio urea is suitably isolated from the reaction mixture byconventional procedures such as extraction. distillation,chromatography, etc. Alternatively, a solution of the N-chlorothio ureain the reaction diluent, preferably after removal of the acid acceptorhydrochloride salt produced in the reaction, is reacted with the urea orcarbamabe (111) according to equation (1) to produce the compounds ofthe invention.

The symmetrical bis-urea sulfides of formula (1) are also prepared byreacting a urea and sulfur chloride as depicted in equation (3):

EXAMPLES EXAMPLE 1 Preparation of N-chlorothio-N-methyl-N-2-fluorophenyl urea A 5.7 g (0.055 mol) sample of sulfur dichloride wasadded dropwise to a mixture of 8.4 g (0.05 mol) N-methyl-N-2-f1uorophenyl urea and 4.7 g (0.06 mol) pyridine in mlmethylene chloride cooled in an ice bath. After the completion of theaddition, the pyridine hydrochloride formed during the reaction wasfiltered. Hexane was added to the filtrate to precipitate someadditional pyridine hydrochloride, which was removed by filtration.Evaporation of the resulting filtrate gave a clear red oil. The nuclearmagnetic resonance spectrum of the oil shows an N-methyl singlet at 3.5ppm (relative to tetramethylsilane). Elemental analysis showed: 708,calc. 13.6, found 13.6; %Cl, calc. 15.1, found 15.4.

EXAMPLE 2 Preparation of N-chlorothio-N-( 3 ,4-dichloropheny1)-N,N-dimethyl urea A 5.7 g (0.055 mol) sample of sulfur dichloride wasadded dropwise to a mixture of l 1.7 g (0.05 mol) of N-(3,4-dichlorophenyl)-N',N'dimethyl urea and 4.7 g (0.06 mol) pyridine in50 ml methylene chloride cooled in an ice bath. After the completion ofthe addition, the pyridine hydrochloride was filtered. Hexane was addedto precipitate some additional pyridine hydrochloride, which was removedby filtration. Evapo ration of the resulting filtrate gave the productas a clear yellow oil. The NMR showed an N',N'-dimethyl singlet at 3.0ppm (relative to tetramethylsilane). Elemental analysis showed:

wherein R, R R and B have the same significance as previously defined.

In general, the reaction depicted by equation (3) is accomplished byadding freshly distilled sulfur dichloride to the urea and the acidacceptor. The reaction is preferably accomplished in a suitable inertsolvent such as those employed for the reactions depicted in equations(1) and (2).

The reaction temperature is usually between 20C. and the boiling pointof the solvent, preferably 0 to 35C. The reaction time is from 15minutes to 12 hours. Stoichiometric amounts of the reactants aregenerally employed, i.e., the molar ratio of urea to sulfur dichlorideis about 2:1 and the molar ratio of urea to acid acceptor is about 1:2.

Asymmetrical bis-urea sulfides may also be prepared by the reactiondepicted by equation (3) by using two different urea reactants.

Preparation of N-chlorothio-N-methyl-N '-3 ,4-dichlorophenyl ure a A9.48 g (0.12 mol) sample of pyridine was added dropwise to a slurry of21.9 g (0.1 mol) N-methylN'- (3,4-dichlorophenyl) urea and 1 1.3 g (0.11 mol) sulfur dichloride in ml methylene dichloride at 2530C. After thecompletion of the addition, pyridine hydrochloride was filtered from thereaction mixture. The NMR spectrum of the reaction mixture showed asinglet at 3.5 ppm (relative to tetramethylsilane) for the N-methylgroup of the N-chlorothio-N-methyl-N'-3,4 dichlorophenyl urea product.

EXAMPLE 4 Preparation of N-chlorothio-NN dirncthyl urea Pyridine I948 g0.12 moll was added dropwise to a solution of 8.8 g (0.1 mol)N,N-dimethy1 urea and l 1.3 g (0.1 1 mol] sulfur dichloride at 2530C.Pyri dine hydrochloride was then filtered from the reaction mixture togive a solution of the N-chlorothio urea product in methylene chloride.The NMR spectrum of the product showed a singlet at 3.5 ppm for the N-rnethyl group and a doublet at 2.95 ppm for the N- methyl group.

EXAMPLE 5 1 -methyl- 3-( 3,4-dichlorophenyl l -ureidoa-naphthyl-N-methylcarbamoyl) sulfide A solution of 0.05 mol ofl-chlorothio-l-methyl-3- (3.4-dichlorophenyl) urea in 50 ml of methylenechloride was prepared by a procedure identical to that of Example 3.l-Naphthyl-N-methyl carbamate, 8.3 g (0.04 mol) was added portionwise tothe chlorothio urea at room temperature Pyridine, 3.9 g (0.05 mol) wasadded and the reaction stored overnight at room temperature. Thereaction was washed with water, washed with sodium bicarbonate, driedover magnesium sulfate, and evaporated under reduced pressure to give abrown oil. The oil was slurried with ether to precipitate a white solid.Recrystallization from chloroform/hexane gave the product,,m.p.123-124.5C. E1 cmental analysis showed: %S, Calc. 7.11. found 7.4; 1C1,calc. 15.8, found 15.8.

EXAMPLE 6 A solution of about 0.05 mol l-chlorothio--l-methyl-Z-(Z-fluorophenyl) urea in methylene chloride was added dropwise to11.65 g (0.05 mol) 3,3-dimethyl-l- (3.4-dichlorophenyl) urea and 4.74 g(0.06 mol) pyridine in 50 ml methylene dichloride. After the additionwas completed. the reaction was stirred for 3 hours at about C andallowed to stand overnight. The reaction mixture was then washed withwater, washed with sodium bicarbonate, washed twice with water, driedover magnesium sulfate and evaporated to give a yel low oil. The yellowoil was crystallized from hot ethanol to give the bis-urea sulfideproduct, m.p., 14954505C Standard analysis gave:

Cale. Found C "c 47.3 49.7 H "t 3.9 3.8 N 13.0 130 S ri 7.4 7.5 ('1 16.516.;

EXAMPLE 7 8 rothio urea was added dropwise to a slurry of 11.7 g I005mol] 3,3-dimethyl- 1-( 3,4-dichlorophcnyl) urea and 3.95 g (0.05 mol)pyridine at about 25C. and the resulting reaction mixture was stirred atabout 25C. for 2% hours. The reaction mixture was then washed withwater, washed with sodium bicarbonate solution, washed with water. driedover magnesium sulfate and evaporated under reduced pressure to give ayellow oil. The yellow oil was slurried in benzene and filtered. Thefiltrate was then washed through a column of silica and evaporated togive a thick oil which crystallized from ether-hexane as a white solid.Recrystallization of the white solid from isopropanol gave the bis-ureasulfide product, m.p., 145l49C. Elemental analysis gave: S, calc. 66,found 6.7; %CI, calc. 29.4, found 30.0.

EXAMPLE 8 Preparation of bis-( l-methyl-3-o-fluorophenyl-l-ureido)sulfide 5.6 g (0.05 mol) of freshly distilled sulfur dichloride in 10 mlof methylene chloride was added slowly to 16.8 g (0i mol) of1-methyl3-o-fluorophenyl urea and 8.5 g (0.106 mol) of pyridine in 250ml of methylene chloride. Solution of the partially dissolved urea waseffected. After being stirred 2 hours at room temperature, the mixturewas washed two times with 200-ml portions of water, dried over magnesiumsulfate, followed by removal of solvent under vacuum. The product waschromatographed on 200 g of silica gel eluting with ether. Thecrystalline product isolated by chromatography was recrystallized frombenzene-hexane giving 5.5 g of crystals melting at l 101 14 C. Thecompound, bis-(l-methyl-3-o fluorophenyl-l-ureido) sulfide, showedelemental analysis as follows: %S, calc. 8.75, found 886; %F, calc.10.38, found 1072. An NMR spectrum of the recrystallized materialfurther identified the product.

EXAMPLE 9 Preparation of bis-( 1 -methyl-3-( 3 ',4 '-dichl0rophe nyl 1-ureid0) sulfide 5.6 g (0.05 mol) of sulfur dichloride in 10 ml ofmethylene chloride was added to a slurry of 21.9 g (0.1 mol} ofl-methyl-3-(3,4-dichlorophenyl) urea and 8.5 g (0.106 mol) of pyridinein 250 ml of methylene chloride. Solution was effected after beingstirred 2 hours. The yellow solution was added to 200 ml water, causingwhite solid to come out of the solution. The white solid was collectedon a filter and the filtrate worked up to yield more crude product. Thefilter cake was recrystallized from ethanol, yielding 3.7 g of whitecrystals of bis( l-methyl-3-(3',4'-dichlorophenyl)- l-ureido) sul fide,melting at 188-192C. The elemental analysis was: %Sc, calc. 6.86, found6.45; %Cl, calc. 30.3, found 27.87.

EXAMPLE 10 Preparation of bis-( l-methyl-3 p-fluorophenyll-ureido)sulfide 5.6 g (0.05 mol) of sulfur dichloride in 10 ml of methylenechloride was added slowly to a flask containing 16.8 g of1-methyl-3-p-fluorophenyl urea (01 mol) and 8.5 g of pyridine in 250 m1of methylene chloride. The resulting green solution was stirred at roomtemperature for 2 hours, then water-washed twice, dried and stripped.The residue was a thick, greenish oil which solidified when cooled.Recrystallization from ethanol in hexane and further washing of thecrystals with hexane resulted in 7 g ofbis-(l-methyl-Ii-pfluorophenyl-l-ureido) sulfide having a melting pointof l23l36C. and the following elemental analysis: %S, calc. 8.77, found8.65; %F, calc. 10.38, found l0.3.

EXAMPLE l l Preparation of: (a) bis-( l-methyl-3-p-chlorophenyll-ureido) sulfide; and

l-methyl-3-p-chlorophenyll-ureido-l '-p-chlorophenyl-3 '-methyl- 1'-ureido sulfide 5 5.6 g of sulfur dichloride in 10 ml of methylenechloride was added slowly to a slurry of l8.5 g of l-methyl-3-p-chlorophenyl urea and 8.5 g of pyridine in 250 ml of methylenechloride. The resultant brown solution separated by chromatography, wasidentified as: (a)

bis-(l-methyl-3-p-chlorophenyl-l-ureido) sulfide having a melting pointof l9ll96C. and chemical analysis as follows: %S, calc. 8.17, found8.18; %CI, calc. l7.78, found 18.18; and (b) l-methyl-3-p-chlorophenyll-ureido-l '-p-chlorophenyl-3 '-methyl- 1 '-ureido sulfide having amelting point of l87l93C. and a chemical analysis of: %S, calc. 8.01,found 8.04; %Cl, calc. l7.l7, found l7.76.

UT] LlTY The sulfides of the present invention are in general herbicidalin both preand post-emergent applications. For pre-emergent control ofundesirable vegetation, these sulfides will be applied in herbicidalquantities to the environment e.g., soil infested with seeds and/orseedlings of such vegetation. Such application will inhibit the growthof or kill the seeds, germinating seeds 10 fective against weed grasseswell as broadleaved weeds. Some may be selective with respect to type ofapplication and/or type of weed.

Preand post-emergent herbicidal tests on representative sulfides of thisinvention were made using the following methods:

Pre-emergent Test An acetone solution of the test sulfides was preparedby mixing 750 mg sulfide, 220 mg of a nonionic surfactant and 25 ml ofacetone. This solution was added to approximately 125 ml of watercontaining I56 mg of surfactant.

Seeds of the test vegetation were planted in a pot of soil and thesulfide solution was sprayed uniformly onto the soil surface at a doseof 100 micrograms per cm The pot was watered and placed in a greenhouse.The pot was watered intermittently and was observed for seedlingemergence, health of emerging seedlings, etc., for a 3-week period. Atthe end of this period, the herbicidal effectiveness of the sulfide wasrated based on the physiological observations. A 0-to-l00 scale wasused; 0 representing no phytotoxicity, l00 representing complete kill.

Post-emergent Test The test sulfide was formulated in the same manner asdescribed above for the pre-emergent test. The concentration of thesulfide in this formulation was 5000 ppm. This formulation was uniformlysprayed on two similar pots of 24-day-old plants (approximately 15 to 25plants per pot) at a dose of 100 micrograms per cm*. After the plantshad dried, they were placed in a greenhouse and then wateredintermittently at their bases as needed. The plants were observedperiodically for phytotoxic effects and physiological and morphologicalresponses to the treatment. After 3 weeks, the herbicidal effectivenessof the sulfide was rated based on these observations. A 0-to-l00 scalewas used; 0 representing no phytotoxicity, 100 representing completekill.

The results of these tests appear in Table I.

TABLE I Herbicidal Effectiveness Pre/Post Compound 0 W C M P L bis-(l-methyl-3-o-fluorophenyll -ureido) sulfide 100/I00 IOU/100 l00/l00100/100 [DO/I00 100/ I00 bis-( l-methyl-3-p-fluorophenyl)-l-ureido)sulfide 98/[00 100/90 IOU/60 l00/l00 /l00 /I00 Bis-l l-methyl-3-(3,4dichlorophenyl)-lureido sulfide l00/l00 80/100 IUD/I00 Bis-(l-methy|3-p-chlorophenyll-ureido)- chlorophenyl-3'-methyll '-ureidosulfide l00/90 99/55 98/ 99/100 lOO/BS l00/98 l-methyl-3(3,4-dichlorophenyl-l-ureido)- (a-naphthyl-N-methylcarbamoyl) sulfide20/45 25/70 80/65 l00/l00 l00/l00 l00/l00 [3-( 2-fluorophenyl)- l-melhyll -ureido [(3',3 '-dimethyll 3,4-dichlorophenyl l-ureido] sulfide100/95 100/95 l00/95 100/100 l00/l00 100/I00 [3( 3.4-dichlorophenyl 1-methyll -ureid0] [3',3'-dimethyl-l 3,4-dichlorophenyl)- l'-ureido]sulfide QB/I00 100/100 98/73 100/100 [DO/I00 100/H10 O Wild Oats (Avenuufulua) W Watergrass (Echinochlm r-rurgulh') C =Cruhgrafls (Digitariasanguirmfis) M Mustard (Brassicu uriensis) L Lambsquartcr (Chenopodiumalbum) and seedlings. For post-emergent applications, the sul fides ofthe present invention will be applied directly to the foliage and otherplant parts. Generally they are ef- The amount of sulfide administeredwill vary with the particular plant part or plant growth medium which isto be contacted, the general location of application,

i.e., sheltered areas such as greenhouses as compared to exposed areassuch as fields, as well as the desired type of control. For pre-emergentcontrol of most plants, dosages in the range of about 0.5 to 20 lbs/acrewill be used. Such administration will give a concentration of about 2to 80 ppm sulfide distributed throughout 0.1 acre-foot. Forpost-emergent application, such as folaiar spray application,compositions containing about 0.5 to 8 lbs sulfide per 100 gal of spraywill be used. Such application is equivalent to about 0.5 to 20 lbssulfide per acre.

The herbicidal compositions of this invention comprise an herbicidalamount of one or more of the above-described sulfides intimately admixedwith a biologically inert carrier. The carrier may be a liquid diluentsuch as water or acetone or a solid. The solid may be in the form ofdust powder or granules. These compositions will also usually containadjuvants such as a wetting or dispersing agent to facilitate theirpenetration into the plant growth medium or plant tissue and generallyenhance their effectiveness. These compositions may also contain otherpesticides, stabilizers, conditioners, fillers and the like.

What is claimed is:

l. A method for controlling undesirable vegetation which comprisesapplying thereto an herbicidally effective amount of a compound of theformula wherein R is hydrogen or alkyl of l to 6 carbon atoms; R isalkyl of l to 6 carbon atoms or phenyl substituted with up to 4fluorine, chlorine, bromine, nitro, alkyl of l to carbon atoms, alkoxyof l to 4 carbon atoms, or up to l trifluoromethyl or trichloromethyl; Rand R individually are hydrogen, alkyl of l to 6 carbon atoms, or phenylsubstituted with up to 4 fluorine, chlorine, bromine, nitro, alkyl of lto 5 carbon atoms, alkoxy of l to 4 carbon atoms, or up to ltrifluoromethyl or trichloromethyl', and R is NR R wherein R is hydrogenor alkyl of l to 6 carbon atoms and R is alkyl of l to 6 carbon atoms orphenyl substituted with up to 4 fluorine, chlorine, bromine, nitro,alkyl of l to 5 carbon atoms, alkoxy of l to 4 carbon atoms, or up to ltrifluoromethyl or trichloromethyl.

2. The method of claim 1 wherein R is -NRR R and R are the same, R and Rare the same and are phenyl substituted with up to 2 fluorine, chlorine,bromine, nitro, alkyl, alkoxy or up to l trifluoromethyl ortrichloromethyl, and R and R are the same and are alkyl.

3. The method of claim 2 wherein R and R are hydrogen and R and R arephenyl substituted with up to 2 fluorine, chlorine, bromine or alkyl.

4. The method of claim 3 wherein R and R are 2- fluorophenyl and R andR" are methyl.

5. The method of claim 1 wherein R is -NR R"; R and R are hydrogen; Rand R are the same and are phenyl substituted with up to 2 fluorine,chlorine, bromine, nitro, alkyl of l to 5 carbon atoms, alkoxy of 1 to 4carbon atoms, or up to l trifluoromethyl or trichloromethyl; and R and Rare the same and are alkyl.

6. The method of claim 5 wherein R and R are phenyl substituted with upto 2 fluorine, chlorine, bromine or alkyl.

,7. The method of claim 6 wherein R and R are pchlorophenyl and R and Rare methyl.

8. The method of claim 1 wherein R is NR R R is phenyl substituted withup to 2 fluorine, chlorine, bromine, nitro, alkyl of l to 5 carbonatoms, alkoxy of l to 4 carbon atoms, or up to l trifluoromethyl ortrichloromethyl', R is alkyl and R is alkyl.

9. The method of claim 8 wherein R is hydrogen, R is 2-fluorophenyl, Ris methyl, R is 3,4-dichlorophenyl, R is methyl and R is methyl.

10. The method of claim 1 wherein R and R individually are alkyl.

11. An herbicidal composition comprising an herbicidally effectiveamount of a compound defined in claim 1 and a biologically inertcarrier.

12. The composition of claim 11 wherein R is NR R R and R are the same,R and R are the same and are phenyl substituted with up to 2 fluorine,chlorine, bromine, nitro, alkyl, alkoxy or up to l trifluoromethyl ortrichloromethyl, and R and R are the same and are alkyl.

13. The composition of claim 12 wherein R and R are hydrogen and R and Rare phenyl substituted with up to 2 fluorine, chlorine, bromine oralkyl.

14. The composition of claim 13 wherein R and R" are Z-fluorophenyl andR and R are methyl.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. I 3 925 05 DATED December 9, 1975 |NVENT0R(S) I Melancthon S.Brown, Gustave K. Kohn It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Title page, [75] Inventors should read Melancthon S. Brown, deceased,late of Berkely, California; by Gustave K. Kohn, administrator, andGustave K. Kohn, Berkely, California.--

Signed and Scaled this Twenty-second D3) 0f March 1977 [SEAL] Arrest.-

RUTH c. msou c. MARSHALL DANN 8 ,0 Commissioner nflatenls and Trademarks

1. A METHOD FOR CONTROLLING UNDESIRABLE VEGETATION WHICH COMPRISESAPPLYING THERETO AN HERBICIDALLY EFFECTIVE AMOUNT OF A COMPOUND OF THEFORMULA
 2. The method of claim 1 wherein R5 is -NR6R7; R1 and R6 are thesame, R2 and R7 are the same and are phenyl substituted with up to 2fluorine, chlorine, bromine, nitro, alkyl, alkoxy or up to 1trifluoromethyl or trichloromethyl, and R3 and R4 are the same and arealkyl.
 3. The method of claim 2 wherein R1 and R6 are hydrogen and R2and R7 are phenyl substituted with up to 2 fluorine, chlorine, bromineor alkyl.
 4. The method of claim 3 wherein R2 and R7 are 2-fluorophenyland R3 and R4 are methyl.
 5. The method of claim 1 wherein R5 is -NR6R7;R1 and R6 are hydrogen; R2 and R4 are the same and are phenylsubstituted with up to 2 fluorine, chlorine, bromine, nitro, alkyl of 1to 5 carbon atoms, alkoxy of 1 to 4 carbon atoms, or up to 1trifluoromethyl or trichloromethyl; and R3 and R7 are the same and arealkyl.
 6. The method of claim 5 wherein R2 and R4 are phenyl substitutedwith up to 2 fluorine, chlorine, bromine or alkyl.
 7. The method ofclaim 6 wherein R2 and R4 are p-chlorophenyl and R3 and R7 are methyl.8. The method of claim 1 wherein R5 is -NR6R7; R4 is phenyl substitutedwith up to 2 fluorine, chlorine, bromine, nitro, alkyl of 1 to 5 carbonatoms, alkoxy of 1 to 4 carbon atoms, or up to 1 trifluoromethyl ortrichloromethyl; R6 is alkyl and R7 is alkyl.
 9. The method of claim 8wherein R1 is hydrogen, R2 is 2-fluorophenyl, R3 is methyl, R4 is3,4-dichlorophenyl, R6 is methyl and R7 is methyl.
 10. The method ofclaim 1 wherein R3 and R4 individually are alkyl.
 11. An herbicidalcomposition comprising an herbicidally effective amount of a compounddefined in claim 1 and a biologically inert carrier.
 12. The compositionof claim 11 wherein R5 is -NR6R7, R1 and R6 are the same, R2 and R7 arethe same and are phenyl substituted with up to 2 fluorine, chlorine,bromine, nitro, alkyl, alkoxy or up to 1 trifluoromethyl ortrichloromethyl, and R3 and R4 are the same and are alkyl.
 13. Thecomposition of claim 12 wherein R1 and R6 are hydrogen and R2 and R7 arephenyl substituted with up to 2 fluorine, chlorine, bromine or alkyl.14. The composition of claim 13 wherein R2 and R7 are 2-fluorophenyl andR3 and R4 are methyl.